Here’s a pretty one, with a fairly curved mesial root. Those canals were skinny and it took some time and some hand instrumentation to get a good pathway.
Endo on a wisdom tooth? Why not. It’s in occlusion, and it opposes a perfectly good upper wisdom tooth. He knows it will take some work to correct the perio defect, and that #31 needs work, but let’s put our fires out 1 at a time.
And here’s why we use a check film before sealing a canal: In my check film, my mesial canals are ok, and the fill is long in the distal canal. This is a try-in, so it can be tailored to fit. Just make a minor adjustment before you seal it.
So what do you do? Don’t over instrument the canal and try to get the next larger size cone to length. Instead, simply cut the tip off of the cone you’re currently using. After doing this, the mesial canals were sealed predictably, and the distal point stuck in the apex like a cork… nice seal. This highlights the importance of conservative instrumentation, and maintaining the integrity of the apical foramen.